Switch collections onto an authorized bank account or saved card

curl --request PATCH \
  --url https://api.fluid.app/api/settings/billing/instrument \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "instrument": {
    "bank_account_id": 3187
  }
}
'

import requests

url = "https://api.fluid.app/api/settings/billing/instrument"

payload = { "instrument": { "bank_account_id": 3187 } }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.patch(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'PATCH',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({instrument: {bank_account_id: 3187}})
};

fetch('https://api.fluid.app/api/settings/billing/instrument', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.fluid.app/api/settings/billing/instrument",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PATCH",
  CURLOPT_POSTFIELDS => json_encode([
    'instrument' => [
        'bank_account_id' => 3187
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.fluid.app/api/settings/billing/instrument"

	payload := strings.NewReader("{\n  \"instrument\": {\n    \"bank_account_id\": 3187\n  }\n}")

	req, _ := http.NewRequest("PATCH", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.patch("https://api.fluid.app/api/settings/billing/instrument")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"instrument\": {\n    \"bank_account_id\": 3187\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.fluid.app/api/settings/billing/instrument")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Patch.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"instrument\": {\n    \"bank_account_id\": 3187\n  }\n}"

response = http.request(request)
puts response.read_body

{
  "billing": {
    "invoicing": true,
    "upcoming": {
      "total_cents": 18420,
      "scheduled_at": "2026-10-01T06:00:00Z",
      "groups": [
        {
          "label": "Payments",
          "amount_cents": 12870,
          "entries": [
            {
              "product_code": "txn_fee",
              "description": "Transaction fee",
              "quantity": "429.0",
              "unit": "transaction",
              "amount_cents": 12870
            }
          ]
        },
        {
          "label": "Mist",
          "amount_cents": 5550,
          "entries": [
            {
              "product_code": "mist_ai",
              "description": "Mist AI usage",
              "quantity": "5550.0",
              "unit": "unit",
              "amount_cents": 5550
            }
          ]
        }
      ]
    },
    "invoices": [
      {
        "number": "FLB-1405-2026-0008",
        "period_start": "2026-08-01T00:00:00Z",
        "period_end": "2026-09-01T00:00:00Z",
        "total_cents": 21630,
        "owed_cents": 21630,
        "collected_at_source_cents": 0,
        "paid_with_credits_cents": 0,
        "status": "finalized",
        "paid_cents": 21630,
        "balance_cents": 0,
        "processing_cents": 0,
        "groups": [
          {
            "label": "Payments",
            "amount_cents": 21630,
            "entries": [
              {
                "product_code": "txn_fee",
                "description": "Transaction fee",
                "quantity": "721.0",
                "unit": "transaction",
                "amount_cents": 21630
              }
            ]
          }
        ]
      }
    ],
    "billing_email": "angela.martin@dundermifflin.com",
    "payment_method": {
      "status": "usable",
      "method": "auto_debit",
      "bank": "PNC Bank",
      "mask": "••••6789",
      "bank_account_id": 3187,
      "instrument_type": "us_bank_account",
      "display": {
        "bank_name": "PNC Bank",
        "last4": "6789"
      }
    },
    "transaction_rates": {
      "reset_period": "monthly_calendar",
      "accumulated_cents": 4829150,
      "minimum_volume_cents": null,
      "tiers": [
        {
          "threshold_cents": 0,
          "rate_percent": "2.9",
          "fixed_cents": 30,
          "current": true
        },
        {
          "threshold_cents": 10000000,
          "rate_percent": "2.5",
          "fixed_cents": 30,
          "current": false
        }
      ]
    },
    "pull_schedule": {
      "frequency": "weekly",
      "next_pull_at": "2026-10-01T06:00:00Z"
    }
  },
  "status": 200,
  "meta": {
    "request_uuid": "7c2e9a41-3b8d-4f62-a1c5-9d0e6f2b8a37",
    "timestamp": "2026-09-30T14:05:11Z"
  }
}

{
  "message": "<string>",
  "error": "<string>",
  "error_message": "<string>",
  "errors": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "message": "<string>",
  "error": "<string>",
  "error_message": "<string>",
  "errors": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "message": "<string>",
  "error": "<string>",
  "error_message": "<string>",
  "errors": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "message": "<string>",
  "error": "<string>",
  "error_message": "<string>",
  "errors": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "message": "<string>",
  "error": "<string>",
  "error_message": "<string>",
  "errors": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}